No abstract

The frequency and mass concentrations of 13 herbicide micropollutants (triazines, phenylureas, chloroacetanilides and trifluralin) were investigated during 2014 in surface, ground and drinking waters in the area of the city of Zagreb and its suburbs. Herbicide compounds were accumulated from water by solid-phase extraction using either octadecylsilica or styrene-divinylbenzene sorbent cartridges and analysed either by high-performance liquid chromatography with UV-diode array detector or gas chromatography with mass spectrometric detection. Atrazine was the most frequently detected herbicide in drinking (84 % of samples) and ground (61 % of samples) waters in mass concentrations of 5 to 68 ng L. It was followed by metolachlor and terbuthylazine, the former being detected in 54 % of drinking (up to 15 ng L) and 23 % of ground (up to 100 ng L) waters, and the latter in 45 % of drinking (up to 20 ng L) and 26 % of ground (up to 25 ng L) water samples. Acetochlor was the fourth most abundant herbicide in drinking waters, detected in 32 % of samples. Its mass concentrations of 107 to 117 ng L in three tap water samples were the highest of all herbicides measured in the drinking waters. The most frequently (62 % of samples) and highly (up to 887 ng L) detected herbicide in surface waters was metolachlor, followed by terbuthylazine detected in 49 % of samples in mass concentrations of up to 690 ng L, and atrazine detected in 30 % of samples in mass concentrations of up to 18 ng L. The seasonal variations in herbicide concentrations in surface waters were observed for terbuthylazine, metolachlor, acetochlor, chlortoluron and isoproturon with the highest concentrations measured from April to August.

The urinary excretion rates of diethyl phosphate and diethyl phosphorothioate and changes in blood cholinesterase activities were studied in fifteen persons self-poisoned either by the organophosphorus pesticide quinalphos (twelve persons) or by chlorpyrifos (three persons). The organophosphate poisoning was always indicated by a significant depression of serum and/or red blood cell cholinesterase activities. The return of serum cholinesterase activity in the range of referent values took more than 30 days and had a different course in different persons. The most rapid increase in red blood cell acetylcholinesterase activity was noted within 24 h after the first treatment with oximes Pralidoxime and/or HI-6. None of the spot urine samples, collected daily after admission of persons to hospital, contained measurable quantities of the parent pesticide. There was no correlation between the maximum concentration of total urinary diethylphosphorus metabolites normalized to creatinine and the initial inhibition of blood cholinesterase activities measured in samples collected on the day of admission to hospital. The excretion of metabolites followed the kinetics of a biphasic reaction. The half-time of urinary metabolites concentration decrease in the fast excretion phase in quinalphos poisoned persons was 5.5-14.2 h (eight persons) and 26.8-53.6 h (four persons) and in chlorpyrifos poisoned persons 3.5-5.5 h. The half-time for the slow excretion phase ranged from 66.5 to 127.9 h in all persons and for both compounds. For a given person, the rates of excretion of diethyl phosphate and diethyl phosphorothioate were about the same. However, in quinalphos poisoned persons the proportions of single metabolites in total diethylphosphorus metabolites varied with the initial maximum concentration of total metabolites.(ABSTRACT TRUNCATED AT 250 WORDS)